1. Field of Invention
This invention relates generally to semiconductor devices, and more specifically to processing a semiconductor light-emitting structure for mounting.
2. Description of Related Art
Semiconductor light-emitting devices such as light-emitting diodes (LED's) provide efficient sources of light and are more robust than incandescent light bulbs and fluorescent tubes. Advancements in LED technology and processing have facilitated the use of such devices as replacements for traditional lighting sources in commercial and residential lighting applications, for example.
It is common practice when mounting semiconductor structures, to underfill gaps between the semiconductor structure and the carrier using an underfill material. The underfill material may be a material, such as an epoxy, which has weak internal or cohesive bonds, and thus has a strong tendency to wet other surfaces, particularly surfaces having a high surface energy. Many materials used for semiconductor mounting surfaces have a high surface energy in comparison with the underfill material, which causes the underfill to wick into gaps, aided by capillary attraction forces. The underfill material is then allowed to cure, thus providing enhanced structural integrity for the device.
A problem may occur in attempting to underfill semiconductor structures having voids using capillary underfilling methods, particularly where the structure has trenches or vias. Many underfill materials do not have low enough viscosity to completely wick into the voids, thus leaving some unfilled gaps therein. Such materials also have a tendency to fill in unintended areas, such as the sidewalls of the device. In some instances an underfill fillet may have to be removed from the sidewalls of the device to facilitate further processing, such as removal of the substrate, for example.